61818 bearing: complete specifications & equivalents
The 61818 is a ISO 15 radial bearing sized 90 x 115 x 13 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 90 mm |
| Outer diameter D | 115 mm |
| Width B | 13 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 19.5 kN |
| Basic static load rating C0 | 17 kN |
| Fatigue load limit Pu | 0.915 kN |
| Reference speed (thermal) | 11000 rpm |
| Limiting speed (mechanical) | 7000 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 280 g |
| Manufacturer designation | SKF 61818 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-24 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-24
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & 61800-series range
| Bore d | 3.543 in |
|---|---|
| Outer diameter D | 4.528 in |
| Width B | 0.512 in |
| ISO bore code | 18 |
| Radial section height (D−d)/2 | 12.5 mm |
| Smallest bore in 61800-series | 1 mm |
| Largest outer diameter in 61800-series | 1820 mm |
| Width range across 61800-series | 1–140 mm |
| Bore position in 61800-series (smallest first) | 29 of 74 |
| Bore above smallest 61800-series size | 89 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61818-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×115×13 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting. |
| 61818-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×115×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61818-RSR-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×115×13 mm envelope per ISO 15; seal variant (OPEN vs RSR) and load ratings differ — confirm sealing and rating before substituting. |
| 61818-ZZ | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×115×13 mm envelope per ISO 15; seal variant (OPEN vs ZZ) and load ratings differ — confirm sealing and rating before substituting. |
| 61818-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×115×13 mm envelope per ISO 15; seal variant (OPEN vs 2RS) and load ratings differ — confirm sealing and rating before substituting. |
| 61818-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×115×13 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 61818-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×115×13 mm envelope per ISO 15; seal variant (OPEN vs RSR) and load ratings differ — confirm sealing and rating before substituting. |
| 61818-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 90×115×13 mm envelope per ISO 15; seal variant (OPEN vs ZZ) and load ratings differ — confirm sealing and rating before substituting. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the 61818 model number is decoded
In the 61800-series (diameter series 8 of ISO 15) the last two digits encode the bore: 61818 carries bore code 18 = 90 mm. Outside diameter 115 mm and width 13 mm come from the ISO 15 boundary-dimensions general plan. With no seal suffix the bearing is open: no shields or seals are fitted and lubrication is supplied by the application. For normal-load mounting with a rotating inner ring on a 90 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. In the SKF catalogue this open execution carries the bare designation; protected variants are ordered separately as -2Z and -2RSH.
Typical equipment & failure modes
Common applications
- lay shafts and idler shafts
- textile machinery
- packaging machinery
- space-constrained gearboxes
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- rolling-contact fatigue spalling after the rated L10 life is exceeded
- brinelling from static overload or hammering during mounting
Selection pitfalls — read before you substitute
- Large bores like the 90 mm of 61818 demand clean, burr-free seats; one raised burr under a ring this size cocks the bearing and concentrates load at the raceway edge, cutting life drastically.
- The 618xx thin section at 90 mm bore has only a 12.5 mm radial section height: it saves space but is highly sensitive to misalignment, shaft deflection and shock loads — verify shaft stiffness before choosing it over a 6218.
- The open 61818 has no lubricant retention: grease escapes and contaminants migrate straight into the 90×115×13 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Storage matters for open bearings: 61818 leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
- Never mix components between two 61818 units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
- Do not quieten a noisy bearing by preloading it: the 61800-series is a deep-groove design, not angular-contact; axial preload raises temperature and shortens grease life.
- The open 61818 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 61818-2Z (shields) and 61818-2RSH (contact seals), not suffix-free 61818.
- The 19.5/17 kN ratings here are SKF Explorer-class figures from catalogue PUB BU/P1 17000/1 EN (Oct 2018); SKF can revise internal geometry and ratings without changing the designation, so treat the catalogue version and date as part of the specification and re-verify for critical drives.
Frequently asked questions
What are the dimensions of a 61818 bearing?
A 61818 deep-groove ball bearing has a 90 mm bore, 115 mm outer diameter and 13 mm width (3.543 × 4.528 × 0.512 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
Are 61818 bearings from different brands interchangeable?
For boundary dimensions, yes: every brand's 61818 uses the same ISO 15 envelope (90×115×13 mm). Load ratings, limiting speeds, clearance, precision class and sealing design can differ, so verify those in the supplier catalogue when substituting.
What internal clearance does 61818 have?
Unless a clearance suffix says otherwise, 61818 is manufactured to normal (CN) radial internal clearance. Tight fits and hot shafts consume clearance in service — for those conditions order the C3 execution of 61818 and verify the residual clearance after mounting.
How should 61818 be mounted?
Apply the mounting force to the ring being fitted: on a 90 mm shaft seat the press load must pass through the inner-ring face only. Induction heating of the inner ring (max 120 °C) is the clean method at this size. Never strike the outer ring, the cage or the seals.
What is the SKF designation and catalogue data for 61818?
In the SKF Rolling Bearings catalogue this size is listed as 61818 — the open (unsealed) execution, 90×115×13 mm per ISO 15. Quoted values: C 19.5 kN, C0 17 kN, Pu 0.915 kN, limiting speed 7000 r/min, mass 280 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61818.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-24. Read our editorial & correction policy.